Lake Vostok has been capped with Antarctic ice for at least 15 million years. Now scientists have drilled 13,000 feet to reach its surface. They'll soon learn what life forms have adapted to that cold, dark locale.

Russian researchers at the Vostok station in Antarctica pose for a picture after reaching the subglacial lake Vostok, Sunday. Scientists hold the sign reading '05.02.12, Vostok station, boreshaft 5gr, lake at depth 3769.3 meters.' The Russian team reached the lake hidden under miles of Antarctic ice on Sunday, a major scientific discovery that could provide clues for search for life on other planets.

From high atop an Antarctic ice sheet, Russian scientists appear to have opened a window on the possibility for life forms beneath the icy crusts ... or on Jupiter's moon Europa or on Saturn's moon Enceladus.

This week, researchers at the bottom of the world announced they had drilled through more than 13,000 feet of ice to reach the surface of Lake Vostok – a body of water roughly the size of Lake Ontario. The lake has been capped with ice for the past 15 million to 25 million years.